This invention relates to linear polyoxyalkylenediamine biguanides and water soluble salts thereof as well as to fungicidal or bacterial compositions and to ophthalmic or contact lens disinfecting compositions containing such biguanides or such salts thereof as the active ingredient therefor.
Bis-guanides and polymeric biguanides having structures differing from those of the present invention are known in the prior art. Such prior art biguanides are stated to have antibacterial and antifungal properties. See, for example, U.K. patent Nos. 702,268; 1,432,345; and 1,531,717. Other types of biguanides such as polyhexamethylene biguanide salts are known, and are stated to be useful as preservatives for cosmetics--see PCT Application WO86/02001, while yet other types of biguanides such as the polyether types and the polyoxyalkylenediamine types are stated to be useful as surfactants and epoxy resin curing agents--see U.S. Pat. Nos. 4,558,159 and 4,403,078.
There are several important advantages of the biguanides (and their water-soluble salts) of the present invention over the prior art biguanides. The unique structure of the present invention biguanides, particularly the alkylene oxide units, e.g. --(CH.sub.2 CH.sub.2 --O)-- and --(CH.sub.2 --CHCH.sub.3 --O)--, can be controlled to provide the desired hydrophilic-lipophilic balance ("HLB") in order to achieve maximum penetration of the cellular structure of the pathogenic organism. The degree of penetration, in turn, is determined by specific primary (e.g. ionic, covalent) interactions between the biguanide and the cell, as well as secondary (e.g. hydrogen bonding, hydrophobic) interactions as well as miscellaneous interactions such as van der Wall and dipole interactions.
Another outstanding property of the present invention is the unique ability of the biguanides to reduce the interfacial surface tension between the biocidal composition and cell and to thus permit improved adsorption on the surface of the cell. Moreover, the unique structure of the present biguanides suggests that they will be less sensitive to any organic matter suspended in aqueous solutions, i.e. less interaction, and therefore more efficacious when foreign matter is present.
When employed in ophthalmic saline solutions, the unique biguanides would be expected to overcome a problem common to prior art ophthalmic saline solutions. That is, ophthalmic solutions containing the biguanides of the present invention are expected to be less likely to adhere to contact lenses when they are washed with such saline solutions because the unique biguanides have significantly higher water solubilities and form stronger hydrogen bonding with water. That is, such biguanides solvate (i.e. interact with water) more readily than prior art biguanides having somewhat similar structures.